RE: Pu239/240 ratio

["Sun, Lin-Shen" <casper@bnl.gov>]

Like University of Utah, our fission track analysis method was developed in
late 80's.  I have asked for this question and look for this answer too.
Because of the radiations from Pu-239 and Pu-240 are difficult to
differentiate by traditional counting methods.  As we have noticed, most of
analytical results are lumped them together.  For one of my paper, I used an
activity ratio of 20:27 for PU-339 over Pu-240 reported by ORNL for fallout
related assessments.